Fertilizers & nutrients
by Plagron
Plagron Pure Zym is a natural enzyme concentrate that breaks down dead root material and organic residue in your soil, releasing locked-up nutrients back into the substrate. Think of it as a clean-up crew for your root zone — it digests what your plants leave behind and turns it into food they can actually use. The result: better oxygen absorption at the roots, a healthier microbial environment, and plants that look noticeably stronger from veg through to harvest.
Plagron has been developing plant nutrition and substrate solutions out of the Netherlands for over 30 years. Pure Zym sits in their organic-compatible range and works as a soil improver rather than a traditional fertiliser. It doesn't feed your plants directly — it makes your existing soil work harder. That's a distinction worth understanding, and one we'll break down properly below.
Dead roots, decaying leaf matter, and organic residue accumulate in soil over time — especially in containers where drainage is limited. This dead material competes with living roots for oxygen and can create anaerobic pockets where harmful bacteria thrive. Pure Zym accelerates the enzymatic breakdown of this organic waste, converting it into absorbable nutrients like nitrogen, phosphorus, and potassium that feed your plants directly through the root zone.
The enzymes in Pure Zym work at the molecular level, chopping up complex organic compounds into simpler forms your plant roots can take up immediately. This process also opens up physical space in the substrate, improving its oxygen absorption capacity. More oxygen at the roots means faster nutrient uptake, stronger cell development, and better disease resistance — your plants spend less energy fighting off root rot and more energy growing.
One thing to flag: Pure Zym is designed for soil and soil-based substrates. It's not suitable for all growing media or hydroponic setups. If you're running a full hydro system or growing in pure coco, check Plagron's compatibility guides first. For soil growers, though, this is one of those products that quietly makes everything else in your feeding schedule work better.
Here's something we see regularly behind the counter: growers invest in top-shelf nutrients and expensive lighting, then wonder why their plants still look sluggish. Nine times out of ten, the problem is below the surface. Compacted soil, dead root mass from previous cycles, or simply a substrate that's been sitting in the same pot for weeks — all of these reduce the root zone's ability to deliver what the plant needs.
Enzymes are the missing link between having nutrients in your soil and your plants actually absorbing them. Without enzymatic activity, organic matter just sits there decomposing slowly, sometimes creating more problems than it solves. Pure Zym speeds that process up dramatically. You're not adding more food — you're making the food that's already there available.
We'd compare it to the difference between having a full fridge and actually cooking dinner. The ingredients are there either way, but nothing happens until someone does the work. Pure Zym does the work.
The 100 ml bottle of Pure Zym mixes at a 1:1000 ratio, giving you 100 litres of working solution. For a small grow with 2–4 plants in medium pots, that's roughly 6–8 weeks of daily watering. If you're running a larger setup — say 8 or more plants — you'll burn through this in about 3 weeks and want to look at a larger format. Plagron offers Pure Zym in 250 ml, 500 ml, 1 litre, and 5 litre sizes for bigger operations.
| Specification | Detail |
|---|---|
| Brand | Plagron |
| Product type | Soil improver (enzyme concentrate) |
| Active ingredients | Natural enzymes |
| Dilution ratio | 1 ml per 1 litre of water (1:1000) |
| Bottle size | 100 ml |
| Yield per bottle | 100 litres of solution |
| Application frequency | Every watering, entire cultivation cycle |
| Suitable substrates | Soil and soil-based mixes |
| Not suitable for | All hydroponic setups; check compatibility |
| SKU | HS1879 |
Complete your Plagron setup with Plagron Alga Grow and Plagron Alga Bloom for a full organic feeding schedule from seedling to harvest. If you're looking for a root stimulator to pair with Pure Zym, Plagron Power Roots works well alongside enzyme products — it encourages new root growth while Pure Zym clears out the old. For soil growers starting fresh, Plagron Lightmix gives you a clean, lightly fertilised base substrate that responds brilliantly to enzyme treatment.
The dosage is straightforward: 1 ml of Pure Zym per 1 litre of water, every time you water, throughout the entire grow cycle. That 1:1000 ratio is consistent across all Plagron documentation, so there's no guesswork involved.
A practical note: if your water temperature is very cold (below 15°C), the enzymes work more slowly. Room temperature water — around 20–22°C — gives them the best conditions to get to work immediately once they hit the soil.
Pure Zym is not a fertiliser. It won't fix a nitrogen deficiency, it won't boost phosphorus during flowering, and it won't compensate for a poor feeding schedule. What it does is make your existing nutrients more available and your soil environment healthier. If your base nutrition is already dialled in, Pure Zym amplifies the results. If your base nutrition is missing, Pure Zym can't create something from nothing.
It's also worth noting that at 1 ml per litre, the 100 ml bottle is genuinely small for anything beyond a compact personal grow. We've had customers come back within a fortnight looking for the larger size. If you're running more than 4 plants, do yourself a favour and size up from the start.
And one more thing — the smell. It's not unpleasant exactly, but enzyme concentrates have a distinct earthy, slightly yeasty scent straight from the bottle. It dissipates once diluted in water, but don't be alarmed when you first crack the cap. That's the biology doing its thing.
There are a handful of enzyme products on the market, and they all claim roughly the same thing. Here's how Pure Zym stacks up against the two most common alternatives we carry.
| Feature | Plagron Pure Zym | Canna Cannazym | BioBizz Bio-Heaven |
|---|---|---|---|
| Type | Enzyme soil improver | Enzyme preparation | Energy booster (amino acids) |
| Dosage per litre | 1 ml | 2.5 ml | 2–5 ml |
| Primary function | Breaks down dead root material | Breaks down dead root material | Stimulates nutrient uptake |
| Suitable for hydro | No (soil only) | Yes | Yes |
| Organic compatible | Yes | Yes | Yes |
If you're growing exclusively in soil and want the simplest possible dosage, Pure Zym wins on concentration — you use less per litre, so the bottle stretches further. If you need hydro compatibility, Cannazym is the better pick. Bio-Heaven works differently altogether — it's an amino acid stimulant rather than a true enzyme product, so it's more of a complement to Pure Zym than a replacement.
Yes. Pure Zym is designed to sit alongside Plagron's full feeding schedules — Alga, Terra, or any of their organic lines. Add it to your nutrient solution last when mixing multiple products in the same watering can.
Plagron states that Pure Zym is designed for soil and soil-based substrates. It's not recommended for all growing media. If you're running straight coco, check Plagron's substrate compatibility chart or consider an enzyme product specifically formulated for coco and hydro systems.
At 1 ml per litre, the 100 ml bottle produces 100 litres of working solution. For a small setup of 2–4 plants watered every 2–3 days with about 2 litres each time, expect roughly 6–8 weeks of use. Larger grows will need a bigger bottle.
Pure Zym contains natural enzymes and is compatible with organic growing methods. Plagron positions it within their organic-friendly product range. If you're growing strictly organic, it fits right in without introducing synthetic compounds to your soil.
Yes. Plagron recommends using Pure Zym with every watering throughout the entire cultivation cycle, from seedling through to harvest. The enzymes keep the root zone clean during flowering when nutrient demand is highest and root health is most critical.
Overdosing enzyme products rarely causes immediate damage, but it's wasteful and can temporarily shift the microbial balance in your soil. Stick to the 1:1000 ratio Plagron specifies. More isn't better here — consistency is what delivers results.
Enzyme concentrates do degrade over time, especially if exposed to heat or direct light. Store the bottle sealed in a cool, dark place. Most growers report consistent performance for at least 12 months from purchase, but check the batch date on your bottle if it's been sitting around.
Last updated: April 2026
